Multi-die integrated circuits (ICs) are a class of ICs in which multiple dies are placed within a single package. A multi-die IC also can be referred to as a “system in a package” or “SiP.” A multi-die IC can include circuit structures that allow the dies to communicate with one another within the single package at faster speeds than would be attainable were the dies to be implemented as separately packaged ICs mounted on a printed circuit board.
In order to function with this increased level of speed and/or efficiency, signals must be able to propagate from one die to another within a multi-die IC. The circuit structures that effectuate the inter-die exchange of signals must be fabricated with at least a minimum level of reliability. Otherwise, yields can decrease thereby increasing the cost of producing multi-die ICs. Avoiding defects within multi-die IC structures is particularly important since a single defect can render multiple dies useless.
For example, one of the structures that can be used to facilitate the transfer of inter-die signals is a die on which one or more other dies can be mounted. The die, sometimes referred to as an “interposer,” can include metal interconnects that propagate signals among the dies mounted on the interposer. Reducing the likelihood of defects within the interposer and connections between the interposer and other IC structures can increase yield significantly.